New traffic diverter on SE Ankeny at 15th.(Photos: J. Maus/BikePortland)

With two new traffic diverters installed in the past week, the City of Portland continues to fulfill its promise to defend the low-stress biking environment on neighborhood greenways.

People who ride or live near North Mississippi and Holman and Southeast Ankeny and 15th should notice fewer cars and lower speeds in their neighborhoods. That’s because of 8-10 large concrete drums filled with soil that are now spread diagonally across those intersections. The idea is to discourage people from driving on neighborhood streets that have been set aside as bike routes.

The new diverters also illustrate how the Bureau of Transportation is now able to move faster on small projects thanks to recent staffing and policy changes (a strong push from grassroots activists at BikeLoudPDX also played a key role). As we reported back in March, PBOT has a new engineer on staff to oversee projects with small budgets. These diverters cost around $5,000, an amount that would struggle for attention alongside much larger projects in PBOT’s capital projects program. With a new staffer these projects can move forward without a stop at the capital projects desk.

Here’s a closer look at the two new diverters…

Holman diverter a secondary measure

If you were hoping to drive up Mississippi to avoid the diverter at Rosa Parks I have some bad news for you.

The new diverter on North Holman and Mississippi isn’t on a neighborhood greenway; but it wouldn’t exist without one. It comes in response to people who were avoiding the North Michigan Neighborhood Greenway because of a diverter installed a few blocks away (on Rosa Parks and Michigan) in 2013. Too many people were driving north on Michigan (to avoid backups on Interstate 5) and then cutting over to Mississippi one block east to avoid the diverter at Rosa Parks. People who live on that one block of Mississippi weren’t happy.

This new diverter will now force people going east on Holman to turn south (right) onto Mississippi and go back to to Ainsworth. The large concrete drums will keep car users from passing through the intersection east-to-west and north-to-south. If all goes according to plan, people who use Michigan during the evening rush as a way to avoid traffic on Interstate 5 will decide it’s just not worth the hassle.

View looking north on Mississippi at Holman.

Looking southeast from the northwest corner of Holman and Mississippi.

One issue of note is that the current design doesn’t make it easy for bicycle users to pass through the median in any direction. PBOT needs to adjust the spacing of the concrete drums so that people can easily bicycle through. They’ve done a much better job at this over on Ankeny…

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Ankeny diverter should tame traffic in growing neighborhood

Inner Ankeny is very busy these days. And not just with cars and bikes. The area is booming with new housing and related commercial development in what could be a poster-child street for Portland’s growing pains.

The cycling situation on Ankeny is similar to that of SE Clinton Street. Both are legacy neighborhood greenways (built as “bicycle boulevards” in the late 1990s) and both are adjacent to quickly-growing commercial corridors (Burnside and Division respectively). PBOT identified six of these older greenways in their 2015 Neighborhood Greenways Assessment Report. Clinton was first on the list for improvements and now it’s Ankeny’s turn. This new diverter is one of many changes coming to the street meant to bring it up to par with current standards.

The Ankeny/15th diverter is very similar to the one on Holman and Mississippi. Large, soil-filled concrete drums are aligned diagonally from the northwest corner to the southeast corner of the intersection. Unlike the Holman diverter, PBOT has made this one much easier for people to bike through. In addition to leaving an opening in the median they’ve also laid down pavement markings to make it obvious where you are expected to ride. While observing it this morning I noticed the opening was wide enough for a standard, two-seater bicycle trailer.

Looking northwest from the southeast corner of Ankeny and 15th.

Ample room to pass through.

Use caution approaching these intersections. People in cars who are confronted with the median might not come to a complete stop and/or might suddenly accelerate into their turn, directly into oncoming traffic (as seen in this photo).

This new diverter should help reduce auto use on Ankeny in both directions. This is great news because Ankeny is one of the most heavily-used bikeways in the city. In some stretches (near SE 28th), the street has more bike trips than car trips.

Another thing that comes with these diverters is a parking restriction on the northeast and southwest corners of the intersections. This was done to aid the auto turning movements, but it will also improve visibility for everyone who uses the sidewalk and street.

And a note of caution for all users of these intersections. People approaching from the east and west do not have stop signs — that goes for bicycle riders and auto drivers. And if you are driving or riding north-south, remember that bicycle riders coming from east and west are not required to stop.

CORRECTION: This article originally stated that each diverter costs around $50,000. That is incorrect. They cost $5,000. Sorry for any confusion.

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144 Comments

Jesse FriedmanJuly 18, 2016 at 12:44 pm

This is great, but do you know of any efforts to improve crossing at both 12th and especially 11th/Sandy on Ankeny? It’s harrowing around there, especially during rush hour.

We could have more diverters if the city did not create the most costly equipment and costly labor methods to install them. – We need more diverters. The $50,000 diverter at N Holman and N Mississippi is actually stopping us from getting closer to #VisionZero People only feel safe in cars because we have so few diverters.

My question to fellow BP readers: What ideas do you have for getting more diverters, faster, and cheaper?

Your ideas?

My ideas: a) More low cost diverters. Involve the people Design a diverter contest. We could have 80 community diverters for the cost of the PBOT designs.

b) Let locals or 95 neighborhood associations spend a safety budget. This bottom up budgeting is what David Bragdon said would fix the backwards Oregon Transportation plan quote: 2015 Transportation Bill – It “was old school, no performance measures” — “Big road widening at the edge of town” — “key projects for key legislators if they vote the right way”https://youtu.be/Pk1rW5S-S5A?t=34m5s

Agree. It seems these are always designed with the primary goal of stopping cars while also happening to still let bikes through instead of letting bikes through easily as a priority with stopping cars as a secondary requirement.

Here are 4 quick examples of how fewer or smaller diverters could be used to create better flow for cyclists and likely cars too in either a diagnol or 4 way right turn config.

Glad to see these diverters go in. However, it’s disappointing that only one treatment is being done on Ankeny. PBOT consciously did not dedicate enough funding for the Ankeny project to allow for more diversion and intersection treatments. There needs to be far more diversion, as well as intersection treatments at Sandy, 12th, and 28th. Diverters – especially ones of a temporary nature – are incredibly cheap, and to only install one on a busy bike corridor is insulting.

The diverters were funded using “small projects” funds so there was no additional budget for additional treatments. However, Ankeny is slated for “constrained” improvements based on the draft Central City Plan and the TSP.

Soren. Good points. We need diverters, but the city ( with intent ) drained too much “small project” funding on excessive staff to design and install these. Then the city cries wolf that they ran out of money and need more. See my video with the paint trucks above. See my full length Bike Portland subscriber story below. The city pits bikes v peds when they take a funding problem and make it worse.

Adam. You said not enough funding. I say we have have enough funding. This is about policy to not allow more diverters that cost less and can be just as safe. The not enough money excuse is propaganda from the city. Hales made the same detour money excuse at the 2015 bike loud rally at city hall with 100 people. Don’t buy the no money lies.

Thanks, I forgot about 20th. Shows how much I ride it I suppose, since the crossings are so bad that I will usually avoid Ankeny altogether. The 11th/Sandy crossing is absolutely criminal. How is anyone at the city okay with a six-way intersection like that not having a traffic signal?

My favorite traffic engineer stated that repaving has reduced the height of the diverter at SE 20th so it is now relatively easy to drive over. BikeLoudPDX asked for bolt-attached posts similar to the ones on 17th and PBOT agreed. Hopefully, this will decrease the drive-throughs that occur there. As I wrote below, Ankeny is slated for additional infrastructure improvements, including one way diversion on each block between 6th and 11th and a traffic circle (circles?) at 11th and 12th.

People were loving these diverters this am — lots of smiles an exclamations of approval. The fast pace of new bike infrastructure installation by PBOT shows that we need to keep the pressure on our elected officials to pay for it!

PBOT is also going to install multiple bolt-attached posts on the diverter at SE 20th as can be seen in the markings:

It’s a fine line, literally. If you make the openings wider, people will drive through them. If you make it more aesthetically pleasing, it is going to cost more. It looks to me like they are using sections of sewer main filled with dirt, which is both cheap and effective. Cutting up the street and pouring concrete medians would be much much more expensive.

The math is easy. Cars are 5 feet wide ( car2go) and wider. Bikes are fine with 4.5 foot gaps. The diagonal line these diverters make is a span of 50 feet. The cement buckets are 5 feet wide. We need only 5 buckets with 5 foot gaps between them. The buckets could be made of wood and assembled by volunteers with reflectors. Dirt and plants installed. The corner poles and stop signs would be the only job of PBOT.

While I agree that diverters can theoretically be cheaply sourced (even homemade), there are probably more than a few objections that PBOT might have not limited to liability should they affect traffic decisions/environment. Paikiala might have some ideas on potential alternative materials.

PBOT does not typically turn away external, private funding, as long as the objects are permitted and adequately marked or warned of. SE Stark/Thorburn residents have funded fire friendly traffic calming, 60th to Gilham that will likely get constructed next spring. PBOT permits and approves Better Block installations. It is the un-pemitted and un-reviewed that expose the taxpayers to liability. The Ankeny/15th install, as you can see from the photos, did not leave the requested 6 foot gap for cyclists.

The lack of a defined next project is part of the issue. A single diverter on such a busy street would also present a concern. two or three diverters might be more acceptable, with consideration for where the traffic will go, like Morris with a signal at MLK. Modifying the circles could be low cost, but their use at T intersections limits this tool as well. I’m a fan of opposing one way shared streets with contra-flow bike lanes. North and south of Knott, and north and south of Morris, heading toward the outlet streets, and maybe one more southbound section at the south end where traffic feeds in from MLK? All three, with signing and striping changes might be achieved for $10k.

To quote someone “‘Safety’ is subjective and hard to define. There is more safe and less safe, but nothing is perfectly safe. the mitigation for objects that people will run into is to warn of the object.”

Agree, wood makes a lot more sense here. I mean, eventually someone is going to run into it and its easier to fix and softer to hit. the last thing we would want is for someone to run into a diverter and get themselves kilt. This might embolden some to demand their removal on the grounds of safety.

>the mitigation for objects that people will run into is to warn of the object.

Except on highways where crash attenuators are used in some places? It makes sense.

75 MPH into a rigid object can be fatal. Water barrels to slow down the car is good. More so when it protects a bridge or other infrastructure. What’s the expected risk to cyclists or drivers of a rigid object in the street on a greenway? I’m guessing fatalities will be much less common.

The manhole rings were chosen based on feedback from a blind pedestrian rightly concerned her guide dog would not be visible behind our tall concrete planters. The objects have to be secure enough to not get pushed around, like the planters on NE Multnomah. These repurposed rings are about $200 each and can be reused in the future.

Given the time it takes to install an intersection, you’re going to have a hard time convincing me this is really the cheap option. if it’s cheaper, but takes twice as long to install as dropping a few k-rails, have we saved anything?

Obviously you have to stop cars from driving through (which we don’t always do), but why do we frequently prevent bikes from having a straight shot through the gap? i’m not sure if it’s intentional traffic calming, or poor design.

It is next to impossible to have a straight shot in both directions that also prevents a car driver going through. That said, Mississippi and Holman is not a bike route of any sort, so the device accommodates them, but is not designed for cycles in the way the Ankeny at 15th diverter is.

How is it impossible to have a straight shot in both directions while preventing a driver going through?

Also, I take issue with the way that you said it’s not a bike route of any sort. Just because it’s not signed as a bike route, doesn’t mean that it’s not. You would probably take issue if I said “since NE Multnomah and NE 16th are not car routes at all, we can block any non-compact car through that intersection.” – Just because something is not a signed route, doesn’t mean that you can exclude cargo bikes and such. What kind of reasoning is that?

Designs of streets are based on the plan for the street. the plan for all streets is embodied in the Transportation System Plan, TSP. This plan classifies all streets in the city for six separate modes. The mode classification defines what a street has to be ‘designed for’ versus what it only has to ‘accommodate’. educate thyself.

Ethan, Your inference of ‘tone’ or emotion comes entirely from within yourself. If you are suggesting that all streets must accommodate a particular design vehicle, nothing in the TSP takes that position. All streets have mode classifications that say what should and should not be designed for. Basic design standards, separate from TSP classifications, might be a better place to push for minimum design vehicles.

As to your other question, about two way straight shot bike paths, do the math. you want the bike through path to be straight and linear. where two streets cross, those crossing bike paths intersect, so you end up with a total of two openings in a diagonal barrier to serve all four bike approaches. If the opening you bike through is one side of a square, then the cross-street bike path is another side of the square and the opening is the diagonal between them. If each side of the square is the 6-foot clear path, the diagonal is 8+ feet wide, ample width for most cars to drive through. If you put a bollard in the middle of the opening to stop cars, you’ve also eliminated the straight through path for bikes.

It looks like those yellow chevron signs are going to lead to conflicts such as in your second-to-last photo*. Those typically mean the road curves, so drivers are not going to expect bikes coming through from any direction. They also clutter/obstruct the view. Just take the signs down — “don’t hit the barrels” is self-explanatory at any legal speed in any weather/visibility conditions in a neighborhood.

* But if this is an uncontrolled intersection, yield-to-the-right applies and the person on a bike should have stopped. Idaho stop signs would sure help (why can’t we just make some with an “except bicycles” placard?)

Before NW/SW 20th or the others in the NW grid? Before the low 100’s (108/109/106/111/104th)? Should we continue doing longitudinal corridors of greenways, or move to a trunk/branch, or center/radiating arms, or grid pattern? The current longitudinal model is great if you want to go from one end to the other, but doesn’t really help people get around in their neighborhood.

I’ll only suggest an answer to the last question: moving around the neighborhood should not be a problem on neighborhood streets. If those streets are not conducive to cycling, they need traffic calming.

As long as they have complete bike facilities, there won’t be a problem moving plenty of auto traffic. Giving auto traffic priority over walking, biking, or transit shouldn’t be the case on any surface street regardless of designation.

A greenway on some combination of 7th and 9th from Broadway to Holman is now funded through the Fixing Our Streets program. The exact alignment hasn’t been decided, however. There will be a major public outreach and design process for that. Putting in a new greenway is very different from fixing an existing one…it’s a major project that is making a major change to existing travel patterns, and is very different from these tiny projects on already existing greenways.

I’m all for more diverters, but unfortunately my B-Line trike does not fit through the one on Ankeny! We utilize the street to hit a few key accounts and will have to adjust routes or use the sidewalks to ride through.

This is one of the things I think is not so great about diverter placement. People driving especially narrow vehicles between diverters may happen, but it’s not a problem that calls for specific engineering.

Also, diverter projects always have side effects. Aside from sometimes hosing already bad traffic on existing roads (e.g. Division) which affects emergency response as well as mobility of those with physical disabilities, motorists seem to get more aggressive if you’re anywhere near a bikeway and choose to take a regular street.

You do know that most of Division was one lane before the redo, don’t you? The only part that was two lanes (for two hours a day) were below 23rd, which is not where most of the congestion is (and what’s there now is mostly due to the Orange Line and UPRR volume increases blocking 11th & 12th).

But previously the parking lanes were used as de-facto passing lanes. Now that Division is a place rather than simply a thoroughfare, people complain about the traffic. But the traffic is there because people choose to be there on purpose. If only there was another way to get everyone to Division without driving…

I think it’s great how many cyclists take Clinton as well as some other bikeways, but I don’t think blocking/diverting traffic is something that should be done lightly.

What I find is that everything is just mucked up because Division doesn’t move at all unless you’re there especially early or late. Between the lack of vehicular movement in a heavily walked area where peds have right of way the roads that feed in are messed up even if you’re on a bike. Division doesn’t just stop at those shops on the hill — it goes for miles and even cyclists have legitimate destinations out there.

Where there is lots of traffic, it can make sense to try to separate bikes from the cars. But I do not favor constantly pushing for separate facilities because it perpetuates the mentality among cyclists as well as drivers that bikes don’t belong on the road.

Even in Portland which has good cycling infrastructure, there are significant areas where road riding is the only option. In any case, cycling infrastructure doesn’t get funded until there’s evidence it would actually be used (i.e. people already out there riding).

Division is screwed up because of the lack of a left turn arrow at 39th, because of the Orange Line/UPRR, and because of the increase in the number of people crossing. The first two are bad (but theoretically remediable), the third is good.

What I don’t like is that everyone blames this on the reconstruction. We’d have the same problems even without it, only the street would be more dangerous to cross, and would have a lot less green.

KB, It is untrue that PBOT only constructs greenways where people are already using the roads. PBOT has constructed greenways where people are still not biking in significant numbers. the new greenways philosophy is more akin to ‘build it and they will come’. For new greenways PBOT uses a minimum crossing volume of 50 and preferred of 100 when determining how to upgrade busy crossings, even if no one is currently crossing there.

So, since a standard car is only six feet wide, you would be fine with six and a half foot wide lanes with concrete on each side. Obviously, that’s nonsense, as is a diverter that one cannot easily ride a cargo bike or a bike with a slightly wider than normal trailer through.

As seen in the 7th image, the planters on Ankeney were placed within the painted “clear zone”, leaving a smaller clear zone than was designed. Can PBOT get out there and move the planters out of the clear zone? Or we can all meet there at 5pm today and DIY it?!

I rode through it this morning and thought “I bet a B-Line bike can’t fit through this”.

Good news Jonathan.. I challenge the city on the $5,000 cost. I guess it is more like $10k. We need these diverters, but the city did a bad job and at excessive costs. Cut through cars are blocked, but so are bikes, and taxpayers would be pissed if they saw the bloat. Bikes in all directions are blocked at Mississippi/Holman. Crews took 4 days to put in the diverter at Mississippi/Holman and this is the video of what they wasted their time with >> https://www.youtube.com/watch?v=nZ2opKQLzOE

I’m filing a freedom of information act to get the cost of all diverters installed in PDX in 2015. I suggest you watch my video. I’m guessing I can paint 70 feet of yellow reflective paint for $40 materials and 1 hour of labor. If I had to rent 3 fully staffed paint trucks for 2.5 hours I’m guessing that would cost me about $2000 alone. You could write an RFP see what contractors respond, and prove me wrong. Compare that to driving 3 massive trucks with 7 crew out, only to find they could not get the job done, and they drove away having done nothing. I’m guessing they came from the Stanton St PBOT yard and logged 2.5 hours from start to finish. And after 2.5 hours nothing got done.

I noticed you, paikiala, only ask questions here that mostly have been answered. It seems you just don’t like the answers. It would be great, Paikala, if you could go out, take photos. Actions speak louder than words when it comes to leaders and building a community. I dare you, act.

lots of guesses without any particular evidence. I watched the video the first time. 2 minutes(?) in a day proves nothing much. You also have no idea where the truck came from, or was going afterwards.

I respond to inaccurate opinions and provide information regarding PBOT policy. Answers and opinion does not equal fact.

Great News! As we forward maybe we should rethink how we place diverters.Instead of the defensive mode we are in, now the real solution for the future would be to think about how to channel cars in the safest way possible. We could place diverters to funnel autos from homes or workplaces as directly as possible to the main auto-ghettos ( highways) without endangering foot and bike users.

PBOT frequently makes the excuse that they won’t install diversion because the road is already under the threshold. This is reactive. I propose addressing the issue from a proactive angle: what do we need to do to ensure this street remains under the threshold?

Isn’t this the exact reasoning used to plan out future light rail lines? At any rate, seeing as how each diverter costs about $5,000 each and provides huge benefits, it’s embarrassing that the city is pushing back so hard on what should be a no-brainer.

So, your equating retrofitting of a legacy greenway with a multi-million dollar alternative transportation plan that is actively supported and funded with Federal transportation funds? PBOT builds greenways where no one is yet riding. PBOT just doesn’t have the budget, or Federal support, to build on the same scale.

I’m not saying build on the same scale. I’m just equating it with the mentality of planning out new rail lines. MAX lines are planned out with the idea of fixing something that will be a problem in the foreseeable future, usually projected motor traffic volume on nearby roadways.

And we know how accurate traffic growth projections are…not. I can’t believe you even went there. Light rail is about using tax dollars to move people more efficiently and affordably. A way to wean us from the single occupant auto vehicle = freedom mythology presented by monied interests.

Well said Adam… PBOT method to measure is flawed. I know that a lot of The people want to stop driving but would only do so if the streets are safe now. PBOT counting cars and other tools will never create the future safety we need

The answer you seek is in the post above your post – “PBOT frequently makes the excuse that they won’t install diversion because the road is already under the threshold. This is reactive. ”

Translated: Rather than see pending problems and be proactive we have a slow reactive PBOT. PBOT will only react if someone dies or a major problem festers. One of the major and flawed ways PBOT measures the need for a diverter is to count. How do they count. Mostly they lay down flawed devices on the road to count tire hits. Those are reactive tools. Then PBOT will guess at what is a car or bike etc. To prove how flawed PBOT tools to measure have become a large number of volunteers did it in person. But even that is limited data. In some ways data is good, in other ways people at PBOT argue that data is more important than common sense of the neighbors say and what bikes depending on cutting through that neighborhood say.

If we don’t want to wind up with more street griddlock we should promote bikes in the highest possible quantity cutting through neighborhoods where they do not live. Car diverters in high quantity are just one of many tools lacking in Portland. We need high speed bus, streets free from single passenger vehicles. We need less taxpayer welfare for cars who drive alone and park. #parkingWelfare Some cyclists want arterial bike lanes everywhere, some don’t feel safe riding an arterial bike lane that has zero protection. So the short term fix is bikes on sidestreets with diverters. With fewer bikes on arterials, your bus lanes free of cars ( Seattle and 5/6th downtown PDX) can be expanded. Want the long term fix, visit Amsterdam.

“Rather than see pending problems and be proactive we have a slow reactive PBOT. PBOT will only react if someone dies or a major problem festers.” the problem with hypothesis is, though you may never prove them, you only need one example to disprove them. Tell me why PBOT has spent so much on new greenways where ‘need’ was not defined?

Your off on the counters as well, or maybe just out of date. The current machines can distinguish between autos, trucks of various sizes and bikes. Your understanding of the technology seems way off.

PBOT uses data because it is more objective, and truthful, than opinion. People are notoriously bad at remembering. there are troves of research on how human perception is not grounded in reality, and is easily influenced.

Amsterdam, and European models so frequently held up as the bright shining example of all that is right with transportation, ignores he social structure in which that system exists, and which does not exist in the US.

Your posts imply an over-arching theme that imagines some man behind a curtain, controlling and all knowing, with unlimited power and resources. It’s a common government conspiracy fallacy. You imagine that if you were the man in charge, you could mold the world to conform to your vision. This ignores the reality of how democracy works. it’s messy. it moves forward slowly, because not everyone shares your vision. “… democracy is the worst form of Government except for all those other forms that have been tried from time to time” – Churchill.

I fully endorse a holistic transportation ‘system’ better than the one we have. I just think your rhetoric gets in the way of you making any progress. Good Luck.

this traffic modification is awful. i bike this route every day and this makes things needlessly complicated. traffic is already diverted virtually at sandy and physically at 20th. this is completely unnecessary and i fear will lead to more accidents (both bike on bike and bike on car).

i’m really not sure what planet you are on to make that statement. a huge amount of vehicles heading westbound on e burnside make a left onto 16th, & then an immediate right onto ankeny, to avoid the burnside/couch couplet, where due to their being a light every single block all the way down to mlk/grand, is usually very, very slow moving.

if PBOT’s traffic counters had not confirmed there was too much auto traffic on the street, i guarantee a diverter would NOT have gone in. they have to justify these things somehow.

I was happy to see these yesterday going to work. Ankeny is my daily commute route and never had many issues with it other than the cut through traffic and the 11th crossing and these should help with the former.

My only feedback is that I think that they could have been spaced out about another foot because it does feel tight going westbound.

sadly, I don’t think the one at Holman and Miss. will discourage drivers, since most that I’ve seen go all the way thru to Rosa Parks blvd, make a right and then a u turn at the light to get onto the freeway. A diverter on Ainsworth and/or Killingsworth would really discourage traffic esp. folks from PCC, and those using it as a cut thru all the way from Fremont.

but isn’t the whole point of diverters to discourage cars from using greenways as a cut thru ? I’m well aware that its not illegal to make a u turn unless marked, any more than its not illegal to drive on greenways.

lovely ! since diverters are proven to reduce traffic lets have have one at Killingsworth and Alberta as well, in the path of the actual greenway not a side street. I’ve had enough of drivers passing unsafely etc to where I just take Vancouver in the pm, and Michigan in the am. Also the traffic counts you cite are 2 years old, there’s been a huge influx of new residents as well as increased traffic going into WA since then.

I have ridden Ankeny multiple times this week and i am still shaking my head at these stupid diverters. Only one bike at a time can pass thru them at a time and this is the busiest greenway in Portland…

How did you determine ‘dangerous’? what manual or design guide is your reference? – citation please. What is your roadway design experience, or how much have you studied the subject? Are you aware of national design guide standards?

* capacity — with only one opening, bicycles must go single file. On a busy bikeway there are often fast bikes overtaking slow bikes (unlike cars, each bike has a different preferred operating speed, so overtaking is almost continuous on a busy route). This adds stress to the ride, costs a bit of time, diminishes the (already subpar) quality of the exercise, and adds potential danger if fast riders take safety shortcuts when overtaking at the approach or exit to the diverter.

* safety — the chevron signs obstruct the view of a person in a car stopped at the stop sign. In broad daylight it’s reasonably possible for a person in a car to make a safe assessment as to whether or not its safe to proceed, but after dark or in the rain the only visible point of a bicycle is a single headlight, so it takes extra effort for a person at a stop sign in a car to peer through the visual clutter of the signs and signposts to see if there’s a headlight coming down the pike.

Compare to the diagonal diverter at N Central and Tyler, where * there are no signposts above bicycle headlight or bicyclist torso level. & * There are four passages through the diverters in the dominant direction.

I checked out the Central and Tyler diverter tonight. The concrete cylinders are higher than the 15th and Ankeny.

So, contrary to my assertion in the above post, it’s not an apples to apples comparison.

Central — taller concrete planters, but chevron signs mounted on the sides of the planters. Ankeny — shorter concrete planters, (so better visibility of people on bikes by people in cars), but chevrons mounted on signposts (for poorer visibility).

I’m not sure which one would be better. But I suspect Central is better — much less clutter.

As for safe passage, I think the spacing of the gaps at Central was pretty narrow, 4′ at widest (tricky getting my 43″ wide trailer through there). Bit the 4 openings would definitely allow for safe passage of more than one bike at a time. Which is lacking on Ankeny.

Ted- you do describe my position (but in a much more constructive, convivial tone 😉

Capacity- Yep, one bike at a time. This is serious bottleneck for the volume of this greenway. Speeds vary cylcist to cyclist and people rush the queue. The barrier system at 20th allows the centre curb to be hopped to bypass the queue.

Visibility- Approaching the diverter is like riding towards a wall. The diverters themselves, parked cars, and chevron signs occlude sight-lines. It is difficult to determine if a car is waiting at the stop sign. Typically a cyclist can see a car easier than a motorist can pick out cyclist on the road.

Delving further, we engage in pattern recognition in order to process and navigate the visual environment below a conscious threshold. The wedge + circle is the front quarter panel of a car, or the combination of basic geometry that makes up headlights/grill/hood/windscreen. If you remove the ability to read these queues, appropriate caution and reaction times are compromised. Personally, I have avoided collision in the past by autonomically braking before consciously registering that a car was in my path of travel (this was while making a 90 degree left turn). I attribute this ability to the phenomena above 😉

I hope that PBOT is engaging the design process at this depth of evaluation, however the actualized product indicates possible and unintentional shortsightedness.

visibility is compromised any time you stick a bunch of stuff in an intersection. previously, i would have greater visibility and therefore reaction time to avoid collision. this evening i almost got hit by a car turning west on ankeny as i traveled east thru the intersection. i had to yell and swerve in order to prevent injury. can you provide data that this modification is “less dangerous” without relying on only a reduction in traffic volume?

also, as someone who had studied architecture, urban planning, and psychology, i would be interested in links to design standards and studies (i am open to having that influence my opinion). i realize i am being a bit hyperbolic (feeling endangered does that), but i do not consider myself to be a complete layperson. i think the intent of the diversion is justified, however, the execution of the traffic modification has room for improvement.

I’d be more inclined to take you seriously if you actually rode this route during said rush hour, especially during the school year. Otherwise you’re just another pdot wonk quoting numbers and getting defensive, without being able to take constructive criticism.

I’m glad you’re here, participating in these conversations in a quasi-unofficial capacity. I always appreciate the data you present & the generally evenhanded responses to questions. I hope the comments from daily users of PBOT’s infrastructure are helpful to you.